; 3.13 点状列表 dotted lists

; 判断是否是正规列表
(defun proper-list? (x)
	(or (null x)
			(and (consp x)
					 (proper-list? (cdr x)))))

(setf x '(a b c)
			y '(a '(b c))
			z '(a . b))

(format t "~A 是正规列表: ~A~%" x (proper-list? x))
(format t "~A 是正规列表: ~A~%" y (proper-list? y))
(format t "~A 是正规列表: ~A~%" z (proper-list? z))
